An application of MRI in functional stereotactic thalamotomy is presented. To estimate the individual anatomic variations of the thalamus prior to stereotactic thalamotomy, a special study using a proton density image that shows myeloarchitectonic features of the thalamus was performed. The proton density MRI was demonstrated to be very useful to determine the safest trajectory and tentative target point. However, as a detailed functional localization of the thalamic subnuclei cannot be yet obtained by MRI, the final target should be decided on the basis of electrophysiological findings.